According to Cisco IOS documentation, the network RIP router configuration command accepts a major network number (without subnets) as its parameter. The common wisdom says that you have to list all major networks attached to your router if you want to run RIP on all interfaces. You could get the same results by using network 0.0.0.0 router configuration command.
Ivan Pepelnjak, CCIE#1354, is the chief technology advisor for NIL Data Communications. He has been designing and implementing large-scale data communications networks as well as teaching and writing books about advanced technologies since 1990. See his full profile, contact him or follow @ioshints on Twitter.